Search

Laser-induced fluorescence spectra of iridium monofluoride (IrF) have been obtained at both low and high resolution. Two transitions have been observed; based on the rotational analysis of the high-resolution spectra, they have been assigned as [A.sup.3][Φ.sub.i]-[X.sup.3][Φ.sub.i] and [B.sup.3] [Φ.sub.i]-[X.sup.3] [Φ.sub.i]. For the X (ground) and B states, only the lowest Ω = 4 components have been observed, while for the A state, the two lowest components, Ω = 4 and 3, were detected. A global fit to all of the high-resolution data (six bands of A-X and five of B-X) yielded a complete set of molecular constants for all three states of both [sup.191]IrF and [sup.193]IrF. The v = 3 level of the [A.sup.3][Φ.sub.4] state was found to be heavily perturbed and many extra lines belonging to the perturbing state were observed for each isotopologue. A deperturbation analysis showed that the perturber is an Ω = 5 state, and molecular parameters for this state were obtained. PACS Nos: 33.20.Ks, 33.20.Sn, 33.20.Tp Nous avons des spectres de fluorescence induite par laser dans du monofluorure d'iridium (IrF) a basse et a haute resolution. Nous avons observe deux transitions et, sur la base d'une analyse rotationnelle des spectres de haute resolution, les avons identifiees comme [A.sup.3][Φ.sub.i]-[X.sup.3][Φ.sub.i] et [B.sup.3] [Φ.sub.i]-[X.sup.3] [Φ.sub.i]. Pour les etats X (fondamental) et B, nous n'avons observe que les composantes les plus basses, Ω = 4, alors que pour l'etat A, nous avons detecte les basses composantes Ω = 4 et 3. Un lissage des donnees de haute resolution (six bandes A-X et cinq bandes B-X) nous donne un ensemble complet des constantes moleculaires pour tous les trois etats de [sup.191]IrF et [sup.193]IrF. Le niveau v = 3 de l'etat [A.sup.3][Φ.sub.4] subit de fortes perturbations et nous avons observe plusieurs lignes additionnelles appartenant a l'etat perturbe pour chaque isotopologue. Une analyse des perturbations montre que l'etat Ω = 5 est a l'origine de cette perturbation et nous avons obtenu ses constants moleculaires. [Traduit par la Redaction], 1. Introduction Transition metal diatomic species are of chemical importance as they can serve as models for bonding and reactivity in more complex transition metal systems [1]. In particular for [...]

This paper theoretically and experimentally investigates the reflective performance of Ir films in the vacuum ultraviolet wavelength region. Ir reflecting layers of different thicknesses on various substrates are calculated and fabricated by the ion-beam-sputtering technique. Their reflectance in the 115 nm to 140 nm wavelength region was measured continuously by a reflectometer located at the National Synchrotron Radiation Laboratory. The testing results show that the reflectance of Si substrates is quite sensitive to the deposited Ir layer thickness, while the reflectance on a quartz or a BK7 glass substrates is higher. The energy of the sputtering ion beam exerts a significant influence on the reflectance of the layer, and the postannealing can cause a substantial decrease in the reflectance. For normal incidence, the reflectance of an Ir film on BK7 glass can reach as high as 30%. OCIS codes: 240.0240, 310.0310, 120.5700, 230.4040.

In connection with the design of a hard-x-ray telescope for the Constellation X-Ray Observatory we measured the reflectivity of an iridium-coated zerodur substrate as a function of angle at 55, 60, 70, and 80 keV at the National Synchrotron Light Source of Brookhaven National Laboratory. The optical constants were derived from the reflectivity data. The real component of the index of refraction is in excellent agreement with theoretical values at all four energies. However, the imaginary component, which is related to the mass attenuation coefficient, is 50% to 70% larger at 55, 60, and 70 keV than theoretical values. OCIS codes: 340.0340, 340.7470, 310.6860, 310.1620, 350.1260.

The NMR, UV-visible absorption, and emission spectroscopy and electrochemical methods were used to synthesize and characterize a highly luminescent novel cationic iridium complex [iridium bis(2-phenylpyridine)(4,4'-(dimethylamino)-2,2'-bipyridine)]P[F.sub.6]. Single-layer light-emitting electrochemical cells with the charged complex as conducting and electroluminescent material sandwiched between indium-tin oxide and Ag electrodes were fabricated, which emit green-blue light with an onset voltage as low as 2.5 V.

The catalytic process of photoinduced hydrogen generation through the reduction of water is investigated. The use of parallel synthetic techniques has facilitated the synthesis of a 32 member library of heteroleptic iridium complexes that was screened, using high-throughput photophysical techniques, to identify six potential photosensitizers for use in catalytic photoinduced hydrogen production.

The synthesis and photophysical characterization of a series of (N,C(super 2')-(2-para-tolylpyridyl)2Ir(LL') [tpy)2Ir(LL')] (LL' = 2,4-pentanedionato (acac), bis(pyrazolyl)borate ligands and their analogues, diphosphine chelates and tert-butylisocyanide (CN-t-Bu) are reported. The electrochemical and photophysical properties of the (typ)2Ir(LL') complexes are discussed in detail.

The solid-state transformations under heating of cis-[Ir(CO)(sub 2)C1(C(sub 5)H(sub 5)N)] are examined by integrating infrared spectroscopy, conventional and bidimensional X-ray diffraction, thermal analysis, and hot stage optical microscopy. The structural changes associated with the solid-state transformations of organometallic compounds can be successfully achieved by integrating different investigation techniques.

The photoluminescence (PL) dynamics of Ir(ppy)(sub 3)-cored dendrimers with the simple molecule Ir(ppy)(sub 3) in solution, blends, and neat films are discussed. Extensive aggregation of Ir(ppy)(sub 3) molecules is indicated by their rough surface with aggregated region of rodlike structure, as obtained by atomic force microscopy, which suggests that the PL quenchers in neat Ir(ppy)(sub 3) films may be excimers.

The new monoclinic IrTe2 phase m-IrTe2 was synthesized at 750 degrees C and 4.5 GPa, and its crystal structure was determined by X-ray powder diffraction. The relative stabilities of the three known and three hypothetical IrTe2 exhibits polymorphs are discussed on the basis of tight binding electronic structure calculations and they indicate the feasibility of preparing the IrS2- and ramsdellite-type IrTe2 phases.

The photovoltaic characteristics of ITO/[(t-bt).sub.2]Ir(acac):CuPc/[C.sub.60]/BCP/Ag organic solar cells (OSCs) are studied. The influence of dopant [(t-bt).sub.2]Ir(acac) on charge carrier collection H(V), device energy loss is discussed.

The magnetic Compton scattering technique is employed to analyze the first and second order magnetic transitions taking place in the Ir doped Ce[F.sub.2] compound. The spin-polarized momentum densities of the system are shown to be highly temperature and field dependent.

Highly efficient single-layer organic light-emitting diodes with reduced efficiency roll-off are shown by using a bipolar host material of 2,5-bis(2-(9H-carbazol-9-yl)phenyl)-1,3,4-oxadiazole (o-CzOXD) doped with iridium complexes as the emissive layer. The multifunctional role of hole trapping and electron transporting of the iridium complex in o-CzOXD has balanced the charge carriers and has broadened the recombination zone, thereby improving the recombination of electrons and holes and suppressing the triplet-triplet annihilation and triplet-polaron quenching processes.

A novel iridium(III) complex is described, where the complex has shown as intramolecular face-to-face [pi]-stacking between the phenyl ring of the dmppz ligand and the pendant phenyl of the pbpy ligand. The high stability is favored by the presence of pendant methyl groups on the dmppz ligands that has hindered the entrance of water molecules rendering the degradation of the complex more difficult.

The physical and photophysical properties are optimized when a fac-tris[1-methyl-5-(4-fluorophenyl)-3-n-propyl-1H-[1,2,4]-triazolyl]iridium(III) complex core is encapsulated by rigid high-triplet-energy dendrons. Bilayer devices with an electron transport layer has given improved external quantum efficiencies and the time-resolved luminescence measurements have shown that quenching of triplets by the electron transport layer used in the bilayer organic light-emitting diodes has limited the performance.

A first report on a novel divergent procedure to synthesize higher generation polyphenylene dendrimers with an Ir(III) core up to G4 as the largest Ir(III) dendrimer is presented. The fabrication of all generation dendrimers in phosphorescent organic light-emitting diodes (PhOLEDs) and the relationship between the Ir(III) dendrimer sizes and the device performances is also reported.

Efficient phosphorescence sensitization (PS) consisting of tris(phenylpyridine)iridium (Ir[(ppy).sub.3]) sensitizers and 4-(dicyanomethylene)-2-t-butyl-6-(1,1,7,7-tetramethyljulolidyl-9-enyl)-4H-pyran) (DCJTB) exciton acceptors in a host material is implemented by a simplified emitting-layer structure with selectively doped DCJTB in the Ir[(ppy).sub.3]-doped region. The codoped region away from the recombination zone peak in the Ir[(ppy).sub.3]-region has improved the PS efficiency without influencing the carrier transport characteristics.

A study related to couple light from a polymer light emitting diode (PLED) into a planar single-mode waveguide via use of evanescent coupling is presented. The coupling efficiency of iridium-based diodes PLED-to-waveguide could be improved about a factor of 3.2% by incorporation of an additional spacer layer between PLED and waveguide.

The mobility of charge carriers is examined in the pristine and phosphorescent material doped 4,4',4'tris(N-carbazolyl) triphenylamine (TCTA) by using time-of-flight photoconductivity technique. The ambipolar transport for holes and electrons is possible by doping TCTA with Ir[(ppy).sub.3] (green dopant) whereas only hole transport with reduced mobility is obtained for Ir[(piq).sub.3] (red dopant).

The synthesis and the photophysical and electrochemical properties of blue emissive Ir(III) complexes, containing both tridentate bis(pyrazolyl)benzene (N^C^N) and bidentate phenylpyridine (N^C) ligands are reported. The results from the density functional calculation shed light on the geometry and energy level of the higher-lying dd states involved in the deactivation process.

A new family of cationic iridium(III) complex, [Ir(N^C^N-dpyx)(N^N^C-phbpy)] that contain two cyclometalating terdentate ligands is reported. The newly created [[Ir(N^C^N)(N^N^C)].sup.+] complexes display electrochemical and photophysical properties that are closely comparable to those of the well established class of tris-bidentate complexes and could be used to generate larger conjugated assemblies.

The isomerization of N,N-trans-mer-heteroleptic iridium complex to a more stable cis-mer-isomer observed during the preparation of vacuum-processed organic light-emitting devices (OLEDs) and reproduced in solution is described. The mixture of isomers could be used to prepare polymer-based devices, which could find application as an emitter of better purity.

The single-crystal X-ray crystallography was used to characterize four polymorphs of [Ir.sup.I][(CO).sub.2](OC(C[H.sub.3])CHC(C[H.sub.3])N(p-tol)). All four polymorphs showed varying degrees of metallophilic interactions between the iridium centers that exhibited strong luminescence at 77 K.

Two novel iridium-europium bimetallic complexes are synthesized. The emission of pure red light from europium(III) is observed under the irradiation of visible light through a 'd-f' energy-transfer course and the single crystal structure of the novel bimetallic complex containing Ir and Eu are determined by X-ray crystallography.

A tripod system is described for biotin-avidin assays, consisting of an energy acceptor, an energy donor and biotin. The neutral sensing system for biotin-avidin assays has offered good sensitivity due to intramolecular energy transfer and increased hydrophobicity associated with the avidin binding site and neutral probe.

White electroluminescent (EL) emission is demonstrated from single-layered solid-state light-emitting electrochemical cells (LECs) based on host-guest cationic iridium complexes. The results have shown that white LECs based on host-guest cationic transition metal complexes is a good alterative for solid-state lighting methods.

A controlled phosphorescence color tuning in a series of cyclometalated heteroleptic Ir(III) complexes containing chromophoric 2-(2-hydroxyphenyl)oxazole-derivative ancillary ligands (LX). The characteristic energy-harvesting phosphorescence is shown in electrophosphorescence devices.

The device characteristics of both red and green phosphorescent organic light emitting diodes (OLEDs) were evaluated and compared with those of the reference p-type matrix of 4,4'-N,N'-dicarbazole-biphenyl (CBP). The results revealed that the main recombination zone position and electron-hole balance change as the matrix material changes which leads to changes in the characteristics of the OLEDs.

A new technique for selective low-temperature syntheses of various facial and meridional tris-cyclometalated iridium(III) complexes has been developed. The technique can also be employed for the development of isomers of other C-N ligands and heteroleptic complexes.

The asymmetric synthesis of various N,O-dibenzylated cyclic [beta]-amino alcohol derivatives through combination with ring-closing metathesis and promoted by optically active key intermediate N,O-dibenzylated 3-amino-1-penten-5-ol is described. The reaction was studies by analyzing the Ir-catalyzed allylic amination of O-protected hydroxyalky-substituted allylic carbonates.

The synthesis of bimetallic [[(ppy)2Ir(mu-L)Ir(ppy)2].sup.2+] complexes is reported as a mixture of three stereoisomers. The electronic absorption and the luminescence properties of the three compounds are investigated.

The report explains the synthesis and electrophosphorescence of a new deep red phosphorescent Ir(III) complex, which is commonly used in polymer light-emitting diodes. These substances can easily solubalize arylsilyl-substituted ligands, exhibiting excellent phase homogeneity.